Home Ingredients DL-185® (Dileucine)
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DL-185® (Dileucine)

Evidence Level
Strong
1 Clinical Trial
4 Documented Benefits
4/5 Evidence Score

DL-185® (NNB Nutrition) is a patented dipeptide consisting of two L-leucine molecules enzymatically bonded together (L-leucyl-L-leucine monohydrate). This structure enables absorption via the PEPT1 peptide transporter — bypassing the saturable passive diffusion pathway of free leucine — delivering 86% more leucine to muscle tissue within 30 minutes versus an equivalent leucine dose. A 10-week double-blind RCT in resistance-trained men demonstrated significantly greater muscle protein synthesis, lower body strength, and muscle endurance vs. both leucine and placebo at just 2 grams/day.

Studied Dose 2,000 mg (2g) once daily; absorbed 185% faster than equivalent leucine dose; clinical RCT: 2g/day × 10 weeks with resistance training
Active Compound L-leucyl-L-leucine monohydrate (dileucine dipeptide) — DL-185® by NNB Nutrition; patented enzymatically bonded di-peptide of two L-leucine molecules

Benefits

Superior muscle protein synthesis vs. leucine

DL-185® delivers 86% more leucine to muscle tissue within 30 minutes compared to the same dose of free-form leucine, translating to a 60% increase in mean myofibrillar fractional synthetic rate. This outperformance stems from absorption via the PEPT1 dipeptide transporter — an active transport mechanism not subject to the saturation ceiling of free amino acid absorption.

Supported by Trial 1

Greater strength gains in clinical RCT

In a 10-week randomized, double-blind, placebo-controlled trial in 34 resistance-trained males, DL-185® produced significantly greater leg press 1RM strength improvements vs. placebo (p=0.02) and outperformed an equivalent leucine dose. Participants following a 4-day/week resistance training program showed meaningful muscle performance advantages with 2g/day dileucine.

Supported by Trial 1

Anti-catabolic muscle preservation

DL-185® demonstrates anti-catabolic properties beyond its anabolic MPS stimulation — reducing muscle protein breakdown markers in preclinical studies. This dual anabolic/anti-catabolic profile makes it particularly valuable for cutting phases, aging athletes with anabolic resistance, or periods of caloric restriction where muscle preservation is critical.

Supported by Trial 1

Sarcopenia and aging muscle support

Aging muscle is characterized by anabolic resistance — a blunted MPS response to leucine that drives age-related muscle loss. DL-185® bypasses the absorption bottleneck that limits leucine effectiveness in aging muscle, making it one of the few ingredients with a mechanistic rationale for addressing sarcopenia at the amino acid delivery level.

Supported by Trial 1

Mechanism of action

1

PEPT1 dipeptide transporter absorption

Free leucine relies on LAT2 amino acid transporters that become saturated at high concentrations, limiting muscle delivery. DL-185® is absorbed via PEPT1 (peptide transporter 1) — a high-capacity active transporter in the intestinal brush border that handles dipeptides and tripeptides. This separate transport pathway achieves faster, more complete leucine delivery to systemic circulation and muscle tissue.

2

mTORC1 pathway activation

Once delivered intramuscularly, dileucine activates the mTORC1 (mechanistic Target of Rapamycin Complex 1) signaling cascade more effectively than free leucine — driving phosphorylation of p70S6K and 4E-BP1, the downstream effectors of muscle protein synthesis. The superior intramuscular leucine delivery achieved by DL-185® produces a stronger and more sustained mTORC1 activation signal.

Clinical trials

1
Dileucine vs Leucine for Strength and Muscle Protein Synthesis — RCT
PubMed

Randomized, double-blind, placebo-controlled trial in 34 resistance-trained males comparing 2 g dileucine (DL-185®) vs 2 g leucine vs placebo with resistance training. Outcomes: leg press 1RM, muscle protein synthesis, body composition. (2024)

34 resistance-trained males.

Dileucine group showed significantly greater leg press 1RM improvement vs placebo (p=0.02). Outperformed leucine group on some measures. Mechanism: dileucine (a leucine dipeptide) may have superior absorption kinetics and mTOR signaling efficiency vs free leucine. Note: small single trial; needs independent replication. Industry-funded.

Side effects and drug interactions

Common Potential side effects

No reported adverse effects in clinical trials at 2g/day
Naturally present in all dietary proteins — well-established safety profile
May be taken with or without food; does not require other ingredients for efficacy

Important Drug interactions

No established drug interactions at clinical dose (2g/day)
mTOR pathway activation — theoretical caution with rapamycin/sirolimus (mTOR inhibitor drugs); consult physician

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Frequently asked questions about DL-185® (Dileucine)

What is DL-185?

DL-185® (NNB Nutrition) is a patented dipeptide consisting of two L-leucine molecules enzymatically bonded together (L-leucyl-L-leucine monohydrate). This structure enables absorption via the PEPT1 peptide transporter — bypassing the saturable passive diffusion pathway of free leucine — delivering 86% more leucine to m…

What is DL-185 used for?

DL-185 is researched primarily for Athletic Performance and Muscle & Recovery. DL-185® delivers 86% more leucine to muscle tissue within 30 minutes compared to the same dose of free-form leucine, translating to a 60% increase in mean myofibrillar fractional synthetic rate.

What is the recommended dosage of DL-185?

The clinically studied dose is 2,000 mg (2g) once daily; absorbed 185% faster than equivalent leucine dose; clinical RCT: 2g/day × 10 weeks with resistance training Always follow the product label and check with a healthcare provider for personal advice.

Is DL-185 safe, and does it have side effects?

For most healthy adults, DL-185 is well tolerated at studied doses. Reported effects can include: No reported adverse effects in clinical trials at 2g/day Naturally present in all dietary proteins — well-established safety profile It may also interact with some medications. DL-185 is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does DL-185 interact with any medications?

Possible interactions include: No established drug interactions at clinical dose (2g/day) mTOR pathway activation — theoretical caution with rapamycin/sirolimus (mTOR inhibitor drugs); consult physician If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for DL-185?

NutraSmarts rates the evidence for DL-185 as Strong (4 out of 5). It is backed by 1 clinical trial and 3 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(3 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Paulussen KJM, Alamilla RA, Salvador AF, McKenna CF, Askow AT, Fang HY, et al. Dileucine ingestion is more effective than leucine in stimulating muscle protein turnover in young males: a double blind randomized controlled trial. J Appl Physiol (1985). 2021;131(3):1111-1122. doi: 10.1152/japplphysiol.00295.2021.PubMedUsed to support: Acute crossover trial in 10 healthy young men found 2 g dileucine raised myofibrillar protein synthesis at rest whereas an equal 2 g dose of leucine did not, backing the claim that dileucine is a more potent MPS stimulus than leucine; very small sample and industry-funded, so preliminary.
  2. Hagele AM, Krieger JM, Gaige CJ, Holley KF, Gross KN, Iannotti JM, et al. Dileucine ingestion, but not leucine, increases lower body strength and performance following resistance training: A double-blind, randomized, placebo-controlled trial. PLoS One. 2024;19(12):e0312997. doi: 10.1371/journal.pone.0312997.PubMedUsed to support: 10-week RCT in 34 resistance-trained men found 2 g/day dileucine increased leg-press 1RM versus placebo and reps-to-failure versus leucine, while 2 g leucine did not, supporting a strength/performance benefit; limited to lower-body measures with no body-composition difference, small per-group n, and sponsored by the dileucine maker (patent-holder authors).
  3. Aguilera JA, Tinline-Goodfellow CT, Lees MJ, Kortebi I, West DWD, Abou Sawan S, et al. Dileucine-supplemented essential amino acids support whole-body anabolism after resistance exercise and serum-stimulated cell-based anabolism. J Int Soc Sports Nutr. 2025;22(1):2590090. doi: 10.1080/15502783.2025.2590090.PubMedUsed to support: Acute trial showing dileucine-fortified essential amino acids supported whole-body anabolism (net protein balance) after resistance exercise plus serum-stimulated anabolism in cell culture, indirectly backing dileucine's anabolic claim; small mechanistic study with indirect endpoints rather than direct muscle MPS, and industry-linked.